3.4
Cooling Outlet. The cooling outlet is set to be ON when the process temperature is above the main set
point (SP1) and OFF when below the main set point. If a normally closed solenoid valve controlling
coolant flow were plugged into this outlet it would be open when the
temperature was ‘too high’ and closed when the
temperature was ‘too low’. This outlet is
Device Type
Restrictions
capable of more sophisticated control for
applications requiring tighter temperature
regulation than ON/OFF action affords.
Incandescent lamps
Infrared heaters
1200 watts
≤
Contact J-KEM to discuss your control needs.
Resistive loads
1800 watts
≤
Devices plugged into this outlet should not
exceed the values in the table at the right. If a
large inductive load, such as a compressor, is used
it may be necessary to add a snubber to this outlet.
Inductive loads:
* solenoids
* transformers
* Relays
* motors
6 amps; 720 watts
≤
1/3 horsepower
≤
3.5
Temperature Sensor Input. Every controller is fitted with a specific type of thermocouple input and
can only be used with a thermocouple of the same type. For the correct temperature to be displayed, the
thermocouple type must match the receptacle type on the front of the controller (Figure 1; # 6). All
thermocouples are color coded to show their type (Blue = type T; Yellow = type K; Black = type J). The
color of the thermocouple plug must match the color of the receptacle on the front of the controller. If the
thermocouple is broken or becomes unplugged, the error message "
inPt
" "
FAiL
"
blinks in the temperature
meter display and the controller stops heating.
3.6
Power Reduction Circuit.
This circuit (8) is the interface to J-KEM’s patented power control
computer which limits the maximum output power delivered by the controller. It determines whether the
controller heats at a very low (1-10 mL), low (10 - 100 mL), intermediate (50 - 500 mL), medium (300 mL
- 2 L), or high (>2 L) power level.The power reduction circuit acts as a solid state variac. This circuit has
an additional setting: “Heat Off” which, when selected, turns heating off and allows the controller to act
as a digital thermometer. The table to the right shows the maximum output power from the controller to
the heater depending on the position of the power switch. The correct setting for this switch is the setting
that supplies adequate power for the heater to heat to the set point in a reasonable period of time while at
the same time not overpowering it.
Heating Liquids. Each power level is associated with a
volume range, which acts as a guide when heating solutions
with heating mantles. When solutions are heated with
heating mantles set the power switch to the range that
includes the volume of solution being heated [Note: this
switch is set to the volume of solution, not the size of the
flask]. For example to heat 250 ml of toluene to 80
o
C in a 1
L round bottomed
Front Panel
Approx. % of
Volume Range
Full Power
1 - 10 mL
3
10 - 100 mL
10
50 - 500 mL
25
300 ml - 2 L
50
2 L
≥
100
flask choose the third power setting (50 - 500 ml) since the solution volume falls within this range. There
are situations when a power level other than that indicated on the front panel should be used:
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